1. Technical Field
The disclosure relates to a power-saving sensing module, more particularly to a sensing module which can sense the touch signal to determine whether to enter the power-saving mode.
2. Related Art
Computer has become more and more important for people's daily life. Not merely as a word processing or computing tool, computer also provides entertainment functions as video and game player. Mouse as an interface of computer improves greatly with computer's function enhancement. The conventional sensing technology applied by a mouse utilizes roller, wheel, and light-emitting diode, and now a mouse may further comprise a laser light source emitting coherent light. Functions of a mouse have extended from cursor control to image zooming, finger identification, and so on. As a result, users can control a computer more conveniently.
Optical mouse as main stream of current mouse can be classified into wired mouse and wireless mouse. Optical mouse with multiple buttons or a single button consumes different electricity quantity. Optical mouse is power supplied by its internal batteries. Generally, optical mouse is designed with a power-saving function because the electricity quantity provided by batteries is very limited.
Optical mouse makes use of image sensor to sense a displacement signal. If the sensor does not sense a displacement signal or the sensed image differential is smaller than a certain threshold value, the mouse will enter the power-saving mode.
However, when the sensed image noise is too big, the sensed displacement signal will not be correct. On the other hand, the image noise may cause the sensed image differential to be too big and thus the mouse cannot enter the power-saving mode.
In addition, when a mouse enters the power-saving mode, a certain time period is needed to determine whether a user continues to operate the mouse. In this time period, the image sensor will detect whether there is a displacement signal and as a result electricity power is consumed. Therefore, if the time period of electricity consume is reduced, power-saving effect can be improved. Furthermore, mouse in power-saving mode also needs a long exposure time which further increases the electricity consume.